644734087 has 12 divisors (see below), whose sum is σ = 681493176. Its totient is φ = 609868080.

The previous prime is 644734037. The next prime is 644734093. The reversal of 644734087 is 780437446.

It is not a de Polignac number, because 644734087 - 2²⁷ = 510516359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644734037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 393033 + ... + 394669.

It is an arithmetic number, because the mean of its divisors is an integer number (56791098).

Almost surely, 2^644734087 is an apocalyptic number.

644734087 is a deficient number, since it is larger than the sum of its proper divisors (36759089).

644734087 is a wasteful number, since it uses less digits than its factorization.

644734087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2766 (or 2747 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 43.

The square root of 644734087 is about 25391.6145016421. The cubic root of 644734087 is about 863.8935085193.

The spelling of 644734087 in words is "six hundred forty-four million, seven hundred thirty-four thousand, eighty-seven".